TOPIC 2 Flashcards
(141 cards)
1
Q
What is the fluid mosaic model?
A
The fluid mosaic model of the plasma membrane is composed of a phospholipid bilateral building the membrane . Also shows cholesterol, membrane proteins and carbohydrates
2
Q
What are the 3 major regions of the generalised cell?
A
Plasma membrane
Cytoplasm
Nucleus
3
Q
Functions of the plasma membrane?
A
Mechanical barrier: Separates two of the body’s fluid compartments.
- Selective permeability: Determines manner in which substances enter or exit the cell.
- Electrochemical gradient: Generates and helps to maintain the electrochemical gradient required for muscle and neuron function.
- Communication: Allows cell-to-cell recognition (e.g., of egg by sperm) and interaction.
- Cell signaling: Plasma membrane proteins interact with specific chemical messengers and relay messages to the cell interior.
4
Q
Function of the cytoplasm?
A
Cellular region between the nuclear and plasma membranes. Consists of fluid cytosol containing dissolved solutes, organelles (the metabolic machinery of the cytoplasm), and inclusions (stored nutrients, secretory products, pigment granules).
5
Q
Function of the nucleus?
A
Control center of the cell; responsible for transmitting genetic information and providing the instructions for protein synthesis.
6
Q
Chemical composition of plasma membrane?
A
Membrane made of a double layer of lipids (phospholipids, cholesterol, and so on) within which proteins are embedded. Proteins may extend entirely through the lipid bilayer or protrude on only one face. Most externally facing proteins and some lipids have attached sugar groups.
7
Q
What is a cell?
A
Basic structural and functional unit of living organisms (smallest unit of life). All organisms are made up of one or more cells
8
Q
What are the 2 types of cells?
A
Somatic- mitosis
Sperm/ ova- meiosis
9
Q
What are extracellular materials?
A
- extra cellular fluid ( interstitial fluid, blood plasma, CSF)
- cellular secretions ( substances aiding digestion, intestinal and gastric fluids that act as lubricants, saliva , mucus and serous fluids
- extracellular matrix ( jellylike, proteins and polysaccharides, molecules assembling into mesh in extracellular space where they serve as universal ‘cell glue’ that helps bind body cells together.
10
Q
What are extracellular materials?
A
Substances contributing to body mass that are found outside of cells.
11
Q
What is a plasma membrane?
A
Flexible membrane that seperate the EF to the Intracellular fluid.
12
Q
What is the phospholipid belayer made up of?
A
Polar hydrophilic head ( with phosphate group) facing EF and IF.
No polar hydrophobic tails ( with fatty acids) facing in
13
Q
What do cholesterol do on the cell membrane?
A
wedges its platelike hydrocarbon rings between the phospholipid tails, which stabilize the membrane, while decreasing the mobility of the phospholipids and the fluidity of the membrane.
14
Q
What do carbohydrates/ glycocalyx do on the cell membrane?
A
consists of gly- coproteins and glycolipids that form a fuzzy, sticky, carbohydrate- rich area at the cell surface.
glycocalyx provides highly specific biological markers by which approaching cells recognize each other
15
Q
What are the types of proteins on the membrane and their functions?
A
Integral proteins
Peripheral proteins
Glycoproteins
16
Q
What are the types of cell junctions?
A
Tight
Desmosomes
Gap junctions
17
Q
Tight junctions?
A
Impermeable junctions that form continuous seals around the cells prevent molecules from passing through the intercellular space.
18
Q
Desmosomes?
A
Anchoring junctions that bind adjacent cells together act like molecular “Velcro” and also help form an internal tension-reducing network of fibers.
19
Q
Gap junctions?
A
Gap junctions: Communicating junctions that allow ions and small molecules to pass are particularly important for communication in heart cells and embryonic cells.
20
Q
What are the passive cell transport methods?
A
Simple diffusion
Facilitated diffusion
Osmosis
21
Q
What is diffusion?
A
tendency of molecules or ions to move from an area where they are in higher concentration to an area where they are in lower concentration, that is, down or along their concentration gradient
22
Q
What increases rate of diffusion
A
Temperature, particle size
not concentration
23
Q
T or F cell membrane is selectively permeable?
A
True
24
Q
What is simple diffusion?
A
Energy- Kinetic energy
Description- Net movement of molecules from an area of their higher concentration to an area of their lower concentration, that is, down their concentration gradient
Examples- Fats, oxygen, and carbon dioxide move through the lipid bilayer of the membrane
25
What is facillitated diffusion?
Energy source- Kinetic energy
Description- Same as simple diffusion, but the diffusing substance is attached to a lipid-soluble membrane carrier protein (carrier-mediated facilitated diffusion) or moves through a membrane channel (channel-mediated facilitated diffusion)
Example- Glucose and some ions move into cells
26
What are the 2 types of facilitated diffusion?
Carrier mediated facilitated diffusion- via protein carrier specific for 1 chemical
Channel-mediated facilitated diffusion- diffusion through a channel protein ; mostly ions selected on basis of charge
27
What is osmosis?
Energy source- Kinetic energy
Description-Diffusion of water through a selectively permeable membrane
Eg. Movement of water into and out of cells directly through the lipid bilayer of the membrane or via membrane channels (aquaporins)
28
What is osmolarity?
The total concentration of all solute particles in a solution is referred to as the solution’s
29
What is tonicity?
ability of a solution to change the shape or tone of cells by altering the cells’ internal water vol- ume
30
What is an isotonic solution?
solutions have the same concentrations of nonpenetrating solutes as those found in cells (0.9% saline or 5% glucose). Cells retain their normal size and shape in isotonic solutions (same solute/water concentration as inside cells; water moves in and out).
31
What is a hypertonic solution?
Hypertonic solutions have a higher concentration of non- penetrating solutes than seen in the cell (for example, a strong saline solution). Cells immersed in hypertonic solutions lose water and shrink, or crenate
32
What is a hypotonic solution?
Hypotonic solutions are more dilute (contain a lower concen- tration of nonpenetrating solutes) than cells. Cells placed in a hypotonic solution plump up rapidly as water rushes into them (Figure 3.9c). Distilled water represents the most extreme example of hypotonicity. Because it contains no solutes, water continues to enter cells until they finally burst, or lyse.
33
Are all passive methods of diffusion specific and saturable? ( max rate of transport )
All passive methods except simple diffusion And aquaporin facillitated diffusion
34
What are aquaporins?
Membrane channels for water molecules
35
What is active transport!
Transport that uses apt to move against or up the concentration gradient
36
What are the types of active transports!
Active transport ( primary and secondary )
Vascular transport ( exocytosis, endocytosis, pinocytosis, phagocytosis, receptor mediated endocytosis)
37
What are the types of vesicular transports?
( exocytosis, endocytosis, pinocytosis, phagocytosis, receptor mediated endocytosis)
38
What is primary active transport?
Energy source is ATP, Transport of substances against a concentration (or electrochemical) gradient. Performed across the plasma membrane by a solute pump, directly using energy of ATP hydrolysis.
Ions
(Eg. Na+, K+, H+, Ca2+, and others)
39
What is secondary active transport?
Energy source is Ion concentration gradient maintained with ATP.
Cotransport (coupled transport) of two solutes across the membrane. Energy is supplied indirectly by the ion gradient created by primary active transport. Symporters move the transported substances in the same direction; antiporters move transported substances in opposite directions across the membrane.
40
What are the types of endocytosis
Phagocytosis- A large external particle (proteins, bacteria, dead cell debris) is surrounded by a pseudopod (“false foot”) and becomes enclosed in a vesicle (phagosome).
Eg. In the human body, occurs primarily in protective phagocytes (some white blood cells and macrophages)
Pinocytosis (fluid-phase endocytosis)-
Plasma membrane sinks beneath an external fluid droplet containing small solutes. Membrane edges fuse, forming a fluid-filled vesicle.
eg. Occurs in most cells; important for taking in dissolved solutes by absorptive cells of the kidney and intestine
Receptor-mediated endocytosis - Selective endocytosis and transcytosis. External substance binds to membrane receptors. Means of intake of some hormones, cholesterol, iron, and most macromolecules
41
What is vesicular trafficking?
Vesicular trafficking
- Vesicles pinch off from organelles and travel to other organelles to deliver their cargo.
Intracellular trafficking between certain organelles, e.g., endoplasmic reticulum and Golgi apparatus
42
What is exocytosis?
Secretion or ejection of substances from a cell. The substance is enclosed in a membranous vesicle, which fuses with the plasma membrane and ruptures, releasing the substance to the exterior.
eg. Secretion of neurotransmitters, hormones, mucus, etc.; ejection of cell wastes
43
Mitochondria structure
Rodlike, double-membrane structures; inner membrane folded into projections called cristae.
44
Mitochondria function
Site of ATP synthesis; powerhouse of the cell.
45
Ribosome structure
Dense particles consisting of two subunits, each composed of ribosomal RNA and protein. Free or attached to rough endoplasmic reticulum.
46
Rough ER structure
Membranous system enclosing a cavity, the cistern, and coiling through the cytoplasm. Externally studded with ribosomes.
47
Smooth ER structure
Membranous system of sacs and tubules; free of ribosomes.
48
Golgi apparatus structure?
A stack of flattened membranes and associated vesicles close to the nucleus.
49
Perioxomes structure?
Membranous sacs of catalase and oxidase enzymes.
50
Ribosome function
The sites of protein synthesis.
51
Rough Er function
Sugar groups are attached to proteins within the cisterns. Proteins are bound in vesicles for transport to the Golgi apparatus and other sites. External face synthesizes phospholipids.
52
Smooth Er function
Site of lipid and steroid (cholesterol) synthesis, lipid metabolism, and drug detoxification.
53
Golgi apparatus functions
Packages, modifies, and segregates proteins for secretion from the cell, inclusion in lysosomes, and incorporation into the plasma membrane.
54
Perioxomes function?
The enzymes detoxify a number of toxic substances. The most important enzyme, catalase, breaks down hydrogen peroxide.
55
Lysosomes structure
Membranous sacs containing acid hydrolases.
56
Microtubules structure?
Cylindrical structures made of tubulin proteins.
57
Intermediate filaments?
Protein fibers; composition varies.
58
Micro filaments structure
Fine filaments composed of the protein actin.
59
Centrioles structure?
Paired cylindrical bodies, each composed of nine triplets of microtubules.
60
Inclusions structure
Varied; includes stored nutrients such as lipid droplets and glycogen granules, protein crystals, pigment granules.
61
Cilia
Short cell-surface projections; each cilium composed of nine pairs of microtubules surrounding a central pair.
62
Flagella structure
Like a cilium, but longer; only example in humans is the sperm tail.
63
Microvilli structure
Tubular extensions of the plasma membrane; contain a bundle of actin filaments.
64
Lysosome function
Sites of intracellular digestion.
65
Microtubules function?
Support the cell and give it shape. Involved in intracellular and cellular movements. Form centrioles and cilia and flagella, if present.
66
Intermediate filaments function?
The stable cytoskeletal elements; resist mechanical forces acting on the cell.
67
Microfillaments
Involved in muscle contraction and other types of intracellular movement, help form the cell’s cytoskeleton.
68
Centrioles
As part of the centrosome, organize a microtubule network during mitosis (cell division) to form the spindle and asters. Form the bases of cilia and flagella.
69
Inclusions functions
Storage for nutrients, wastes, and cell products.
70
Cilia function
Coordinated movement creates a unidirectional current that propels substances across cell surfaces.
71
Flagella function?
Propels the cell.
72
Microvilli function?
Increase surface area for absorption.
73
Nucleus structure
Largest organelle. Surrounded by
| the nuclear envelope; contains fluid nucleoplasm, nucleoli, and chromatin.
74
Nucleus function?
Control center of the cell; responsible for transmitting genetic information and providing the instructions for protein synthesis.
75
Nuclear envelope structure?
Double-membrane structure pierced by pores. Outer membrane continuous with the endoplasmic reticulum.
76
Nucleolus struture
Dense spherical (non-membrane-bounded) bodies, composed of ribosomal RNA and proteins.
77
Chromatin structure
Granular, threadlike material composed of DNA and histone proteins.
78
Nucleolus function
site of ribosome subunit manufacture.
79
Chromatin function?
DNA constitutes the genes.
80
Phases of cell cycle?
```
G1 - growth 1
S- growth and DNA synthesis
G2- Growth and final preparations for division
Prophase( mitosis)
Metaphase(mitosis)
Anaphase (mitosis)
Telophase( mitosis)
Cytokinesis
```
81
mRNA role
Messenger RNA (mRNA), relatively long nucleotide strands resembling “half-DNA” molecules (one of the two strands of a DNA molecule coding for protein structure). mRNA carries the coded information to the cytoplasm, where protein synthesis occurs.
82
rRNA role
Ribosomal RNA (rRNA), along with proteins, forms the ribosomes, which consist of two subunits—one large and one small. The two subunit types combine to form func- tional ribosomes, which are the sites of protein synthesis.
83
tRNA role
Transfer RNA (tRNA), small, roughly L-shaped molecules that ferry amino acids to the ribosomes. There they decode mRNA’s message for amino acid sequence in the polypeptide to be built.
84
What happens in trascription?
transcription transfers information from a DNA base sequence to the complementary base sequence of an mRNA molecule.
85
What happens in translation?
In the translation step of protein synthesis, the language of nucleic acids (base sequence) is translated into the language of proteins (amino acid sequence).
86
What are the 4 types of CONNECTIVE tissue?
Connective Tissue Proper
Cartilage
bone Tissue
blood
87
What are the types of tissue?
Epithelium
Connective
Nervous
Muscular
88
What are the subclasses if proper connective tissue?
```
1. Loose connective tissue
● Areolar
● Adipose
● Reticular
2. Dense connective tissue
● Regular
● Irregular
● Elastic
```
89
What cells are found in proper connective tissue
Fibroblasts
Fibrocytes
Defense cells
Adipocytes
90
What is in the matrix of proper connective tissue
Gel-like ground substance
| All three fiber types: collagen, reticular, elastic
91
General features of connective tissue proper?
Six different types; vary in density and types of fibers
Functions as a binding tissue
Resists mechanical stress, particularly tension
Provides reservoir for water and salts
Nutrient (fat) storage
92
Subclasses of cartilage connective tissue?
1. Hyaline cartilage
2. Elastic cartilage
3. Fibrocartilage
93
Cells in cartilage connective tissue?
Chondroblasts found
in growing cartilage
Chondrocytes
94
Matrix of cartilage connective tissue?
Gel-like ground substance
| Fibers: collagen, elastic fibers in some
95
General features of cartilage connective tissue?
Resists compression because of the large amounts of water held in the matrix
Functions to cushion and support body structures
96
Bone connective tissue subclasses?
1. Compact bone
| 2. Spongy bone
97
Cells found in bone connective tissue?
Osteoblasts Osteocytes
98
What is in the matrix of bone?
Gel-like ground substance calcified with inorganic salts
| Fibers: collagen
99
What are General features of bone connective tissue?
Hard tissue that resists both compression and tension
| Functions in support
100
What cells are in blood?
Erythrocytes or red blood cells (RBC)
Leukocytes or white blood cells (WBC)
Platelets
101
What is In the matrix of blood
Plasma No fibers
102
General features of blood connective tissue?
A fluid tissue
| Functions to carry O2, CO2, nutrients, wastes, and other substances (such as hormones)
103
Epithelial tissue function?
Epithelial tissue forms boundaries between different environments, protects, secretes, absorbs and filters. It is found 1) on linings of digestive tractorgand and other hollow organs,2) glands ( Eg. Pancreas) 3) skin surface ( epidermis)
104
Epithelial tissue characteristics?
polarity- one part of cell faced Bottom and one part facing either an organ or the outside of the body. The basic part of cell has different functions to the apex of cell
All cells are in contact
Avascular but innervated ( receives all nutrients through underlying connective tissue)
Regeneration (does a lot of cell division.)
105
Classifications of epithelial tissue?
Layers-
Simple ( one cell thick)
Stratified (several cells thick)
```
Shape
Squamous ( flat structure)
Cuboidal ( dice)
Columnar ( longer, column)
Glandular ( specific, part of epithelium....)
```
106
What is Simple squamous Epithelial tissue? :
single layer of flattened cells with disc shaped central nuclei and sparse cytoplasm; the simplest of the epithelia
107
Function and location of simple squamous epithelial tissue?
Function: allows materials to pass by diffusion and filtration in sites where protection is not important; secretes lubricating substances in serosa ( linings of ventral body cavity)
Location: kidney glomeruli, air sacs of lungs, heart linings, blood vessels and lymphatic vessels: serosae.
108
What is simple cubodial elithelial tissue?
single layer of cube like cells with large, spherical central nuclei.
109
Simple cubodial epithelial tissue location and function
Function: secretion and absorption:
Location: kidney tubules; ducts and secretory portions of small glands; ovary surface
110
What is simple columnar epithelial tissue?
Simple columnar: single layer of tall cells with round to oval nuclei; many cells bear microbiology, some bear cilia; layer may contain mucus secreting unicellular glands ( goblet cells)
111
Simple columnar epithelial tissue location and function?
Function: absorption; secretion of mucus , enzymes, and other substances; ciliated type propels muscu( or reproductive cells ) by ciliary action.
Location: non ciliated types lines most of the digestive tract ( stomach to rectum), gallbladders, and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes and some regions of the uterus.
112
What is peudostratified columnar epithelial tissue?
single layer of cells of differing heights, some not reaching the free surface; nuclei seen at different levels, may contain mucus secreting cells and bear cilia
113
Pseudo stratified columnar epithelial tissue location and function?
Function: secrete substances, particularly mucus; propulsion of mucus by ciliary action.
Location: ciliated variety lines trachea and most of the upper respiratory tract; non ciliated type in males sperm carrying ducts and ducts of large glands
114
What is stratified squamous epithelial tissue?
typical tissue for skin. 2 types keratinised or non keratinised. Thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers.
115
Location and function of stratified squamous epithelium?
Function:Protects underlying tissues in areas subjected to abrasion.
Location:Nonkeratinized type forms the moist linings of the esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin, a dry membrane.
( keratinised means they contain protein keratin which makes skin thougher and provides even more protection
Skin at top often dead
Non keratinised Wherever out skin folds inwards into our body Eg, mouth, anus, vagina, esophagus ( everver a connection to outside...)
116
What is transitional epithelium?
Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamouslike, depending on degree of organ stretch.
Flexible and stretchy good for bladder
Over stretching can make connection between cells break preventing bladder from rebounding. Bladder shouldnt be left to overfill
117
Function and location of transitional epithelium
Function:Stretches readily, permits stored urine to distend urinary organ.
Location: Lines the ureters, bladder, and part of the urethra.
118
What are the glandular epithelium?
Endocrine- no duct. Secrete hormones or products into interstitial fluid. Have a lot of blood supply around them. Blood carries to other organs.
Exocrine- have a duct that transports secretions to epithelial surface. Can also be single cells ( cell will release products and will get out via exoxytosis) Eg, mucus or goblet cells which produce mucus
119
Holocrine vs merocrine glands...?
Holocrine vs merocrine glands...?
120
Muscle tissue characteristics
```
well vascularised ( needs nutrients and energy for moving
Have myofillaments ( moving parts)
Close connection to nervous system
```
121
Muscle tissue classifications
Classification
smooth
Striated
Cardiac
122
Skeletal muscle description, function and location
Skeletal muscle: long, cyndrical, multinucleate cells; obvious striations
Function: Voluntary movement; locomotion; manipulation of the environment; facial expression; voluntary control.
location:In skeletal muscles attached to bones or occasionally to skin.
123
Cardiac muscle description, function and location
Branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs).
Function: As it contracts, it propels blood into the circulation; involuntary control.
Location: walls of the heart.
...
Each muscle cell has one nucleus.
124
Smooth muscle description, function and location
Spindle-shaped (elongated) cells with central nuclei; no striations; cells arranged closely to form sheets.
Function: Propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control.
Location:Mostly in the walls of hollow organs.
Cells much looser, involuntary
125
Nervous tissue characteristics
responds to stimuli
Major regulator of homeostasis and body functions
Transmits electrical impulses
126
Nervous tissue classifications
```
nerve cells
Supporting cells (glia)
```
127
Nervous tissue description
Neurons are branching cells; cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are nonexcitable supporting cells.
Neuron has...
Axon, Dendrites, Cell body
128
Nervous tissue function and location
Function: Neurons transmit electrical signals from sensory receptors and to effectors (muscles and glands); supporting cells support and protect neurons.
Location: Brain, spinal cord, and nerves.
129
What are the different tissue adaptations
Atrophy= decreased cell size,
Hypertrophy= increased cell size
Hyperplasia= increased cell number
Meta/ dysplasia= change cell type
130
Tissue repair stages
First stage acute inflammation which forms basis of tissue repair
Then organisation restores the blood supply
Then maturation /regeneration and fibrosis effect permanent repair
131
Where do the tissues develop from
Epithelial comes from all layers
Muscle and connective tissue mainly comes from mesoderm
Nervous comes from ectoderm
Inner lining of digestive endoderm
132
_______are important and common unicellular exocrine glands.
Goblet cells
133
Where do exocrine glands secrete substances
All exocrine glands secrete their products onto body surfaces (skin) or into body cavities.
134
Where are simple squamous cells found a.
Simple squamous cells line walls of the air sacs of the lungs and blood vessels.
...kidney glomeruli, air sacs of lungs, heart linings, blood vessels and lymphatic vessels: serosae...
135
Where is stratified cubodial cell’s found?
Stratified cuboidal epithelium is quite rare in the body, mostly found in the ducts of some of the larger glands (sweat glands, mammary glands). It typically has two layers of cuboidal cells.
136
What type of epithelial cells line digestive tract
Simple columnar
137
Where is stratified cubodial tissue found?
Mostly found in the ducts of some larger glands ( sweat glands, mammary glands)
138
Where is pseudo stratified columnar epithelial found?
Upper respiratory tract
139
What epithelial tissue is in epidermis?
Stratified squamous epithelium
140
Where does simple columnar epithelial line
Walls of small ducts of glands and kidney tubules
141
Simple cubodial tissue function
Secretion and absorption as they are located at kidney tubules and secretory portions of small glands and also ovary surface
